There is actually no ready-made Activation list. The documentation states that Activation objects cannot be created by the user, and can only be retrieved from the system. In fact it would make no sense to create an Activation object, as it occurs only when, before (or within) a Run(), a certain rule is likely to be fired. Also, being Activations mainly a sort of "temporary" objects, they have no name... hence the absence of a "list of activations" (the List() functions, with few exceptions, just provide lists of *names*). However, the possibility to walk through the list of current activations is provided by the "iteration functions":
InitialActivation() (returns the first activation as an *object*)
Activation.Next() (returns the activation that follows as an object).